Optical and electrical studies on MgTiO3– Ba5Nb4O15 composite thin films for integrated microwave circuit applications

Abstract

A correlative study on optical and electrical properties of MgTiO3 (MTO) -Ba5Nb4O15 (BNO) composite thin films (MTBN) with respect to film thickness (260–450 nm) is reported. The optical bandgap energy of MTBN composite thin films (3.76 eV–3.65 eV) are found to be intermediate to MTO (3.44 eV) and BNO (3.85 eV) monoliths. Further, the optical dispersion in MTBN composite thin films can be defined by Cody-Lorentz dispersion law. Higher photoluminescence (PL) emission intensity and shorter carrier lifetime (0.8376 ns) ascribed to local symmetry break is observed for 450 nm film. Moreover, the Mott's variable range hopping mechanism was dominant conduction process in the MTBN composite films. Further, density of states near the Fermi level were found to be around 7.85×1018 eV−1cm−3 - 3.478×1019 eV−1cm−3 for 260 nm–450 nm MTBN films. The obtained optical and electrical properties prospect a potential application of the MTBN composite thin films in integrated microwave circuits.